Our principal research objective is to establish a method of detecting cataract formation due to protein aggregation in living systems at its very early stage, even before the appearance of visible opacification. We have recently discovered that it is possible to measure the diffusivity of lens proteins in intact whole lenses using the technique of laser scattering spectroscopy. Since diffusivity is inversely related to the radial size of the proteins, we are now able to detect in the intact lens protein aggregation associated with cataractogenesis. Based on this new discovery we propose to establish a method of observing protein aggregation in the lenses of living animals. Using such in vivo instruments, we will carry out a wide variety of animal experiments which investigate the relationships between lens opacification and protein aggregation in a lens under various metabolic conditions.